Autobiographical Memory

Each of us is exposed to a world full of information and sensations from the moment of our birth. Autobiographical memories have the potential of being created through experiences like first kisses, sad goodbyes, warm summer breezes, and familiar places. Of course, not all of them do.

Understanding what we remember about our past and why we remember it has long been an intriguing topic for Scientists. However, we are presented with a problem when trying to figure out how to study autobiographical memory. Painstaking detail can be taken to plan out experiments to test many other kinds of memory in the laboratory but that approach doesn’t work so well for autobiographical “episodic” memories. These memories are created throughout our lifetime and everywhere along the way.

A simple method to study autobiographical memory was pioneered by Sir Francis Galton, a nineteenth century English psychologist. Today, we continue to use a modified version of this method. Galton decided to use a list of common everyday words in order to go fishing, as it were, for associated memories. On four occasions, using the same cues to try and catch his recollections, Galton threw out his net of words.

Experiencing difficulty pinpointing when the recollected events had actually occurred became one of Galton’s key findings. The fact that the same associations were often produced over and over again by his brain was another key finding. In summarizing his findings Galton wrote: “This shows much less variety in the mental stock of ideas than I had expected and makes us feel that the roadways of our minds are worn into very deep ruts.”

The distribution of autobiographical memories over time was studied once again by researchers in the 1970s who modified Galton’s cue word method. Through these studies it was determined that college students who were being tested reported greater memories from the recent past rather than the distant past which ultimately supported the “power law of forgetting”. Based on numerous studies of other types of memory, the “power law of forgetting” predicts that, shortly after being learned, most information will be forgotten.

If you were to graph the relationship between time and forgetting, in fact, you would see a steep slide with the rate of forgetting eventually leveling off. According to the “power law of forgetting”, this leaves a small but steady core of knowledge.

Psychologists began studying autobiographical memories by older and middle aged people as life expectancy continued to increase and the desire to understand age-related changes in cognition grew. What the psychologists found when comparing time and forgetting – to their surprise – was a graph that resembled a bumpy roller coaster rather than a steep slide. In the beginning of the roller coaster ride few autobiographical memories were reported with a five-year period of “childhood amnesia”. That five-year period ended with a sharp incline of memories that corresponded to the most recent past. What surprised the psychologists was what they refer to as a sizeable “bump” of memories from adolescence and young adulthood. The availability of large numbers of memories from the “bump” years appears to remain constant for healthy adults well into their 90s – unlike many other kinds of memory which can change with age.

Researchers have not been able to come to agreement on an explanation for the “bump”. One theory, which has subsequently been discredited, suggested that the “bump” (or ‘reminiscence effect’) is simply a reflection of the years when the brain is functioning at its very best. Another theory suggests that there are no similar experiences to interfere with how well things are being learned or remembered when people are young because many events during the “bump” period are brand new and exciting. A third theory suggests that experiences in our teens and twenties are used to establish a narrative about who we are and that, once our identity has been established, fewer new memories need to be incorporated.

What is clear, however, is that there are a multitude of reasons to remember our past.

When we want to share old stores with family and friends we sometimes intentionally reminisce. Retelling stories from our past in social settings is something that all children seem to learn early on in their lives.

Flashbulb memories are created by events that are extremely important or incredibly surprising. It is very likely that you can remember exactly where you were and what you were doing when you heard the news that the Challenger Space Shuttle exploded, or that airplanes hit the World Trade Center, or that man had set foot on the moon, or the news that John F. Kennedy was assassinated.

Sometimes it’s a fleeting familiar feeling that summons a memory to pop up out of the blue. French novelist Marcel Proust described this as “(T)he smell and taste of things remain poised a long time, like souls, ready to remind us”.

Autobiographical memories have been shown in studies to not necessarily be accurate. They are, rather than being precise recollections, creative constructions that change over time as new circumstances are introduced. The ability to recall the details of an event, who participated in the event, and even the life periods in which the event occurred can all be affected by illness or trauma.